The ACPI wakeup tool is a small command line
application that allows your Linux computer to
wake up from soft-off (S5) at a predetermined
time. It is ideal for situations where you want to
have a server turn off at night but power itself
on in the morning automatically.

AWBMTools is a pair of programs to convert between 256-colour TIFF files and the custom AWBM format used by the EPIA motherboard's Award BIOS for full-screen bootlogos. It might work with other motherboards too, but has only been tested with EPIA.

AdvanceCD is a bootable live CD, DVD, and USB disk
that contains a minimal Linux distribution
containing the AdvanceMAME emulator. You can boot
it on any PC and play the contained games without
any installation.

atftp is a client/server implementation of the TFTP protocol that implements RFCs 1350, 2090, 2347, 2348, and 2349. The server is multi-threaded and the client presents a friendly interface using libreadline. The current server implementation lacks IPv6 support.

The Auditor security collection is a live-system
based on KNOPPIX. It provides tools for analyzing
the security of a system. It features a menu
structure that reflects the stages of a security
check: foot-printing, analysis, scanning,
wireless, brute-forcing, cracking. In addition to
about 300 security tools, the collection includes
background information regarding standard
configuration and passwords, truly extensive word
lists, and more mundane productivity tools.

Autopoweroff is a script that shuts down a
computer at a specific time, but only if some
conditions are met. It works well on home
routers/firewalls where the machine can be
switched off every night and powered back up in
the morning. It can be configured to only shut
down the server after any computers which depend
on the server for Internet access have been shut
down.